Hi 6464,

That parts guy must have stocked that large number of different coolants to help his customers avoid mixing formulas (the OAT long life coolants are very sensitive to being mixed with other formulas). There was a very big class action lawsuit back at the dawn of OAT extended life coolants caused by the public's (and their mechanic's) lack of understanding about that sensitivity.

When using the old fashioned, "classic" IAT coolant (usually colored green, but, again, there is no standardization so it is necessary to read the label carefully), those are traditionally OK with being intermixed, because their chemistry was simpler, and because they get flushed every few years anyway.

As Alex pointed out, also make sure about any % of water already added to what you buy so your final mix will be as intended (or buy a simple hygrometer to confirm the result yourself and adjust accordingly).

Norm

10% mix of water and good old-fashioned blue anti-freeze is all you need.  Make it a bit stonger in the winter according to climate.

Off the shelf coolant is usually about a 50% mix, and severly diminishes the performance of our already overworked cooling systems.

Norm, thanks for all that info. The second auto parts supplier must have had 12 to 15 different coolants on display one for each car manufacturer.  Now  my instinct would be to buy the cheapest green color coolant. Are you saying I should, lets say buy PEAK brand green color coolant and stay with that vs buying another brand because it's on sale?

Here is a more wordy reply based on some research on this subject I did about 4 years ago:

OAT is designed for aluminum cooling systems, and lacks the corrosion protection needed for lead based solders used in our copper/brass radiators (the tiny amount of aluminum involved in the water pump itself doesn't matter much, as that surface area is really small, compared with the radiator). OAT without silicates is designed for use in modern systems designed for it, and will last for very long service intervals in those systems (the silicates can form solids / gel if the Ph drops after ~ 24 months). The nature of fully aluminum cooling systems is that they can get to use specific chemicals that are stable over long intervals. OAT is not recommended for our systems.

IAT is the "classic" coolant, and must be changed every 24 months because it breaks down as the Ph changes in the mix over time, as the phosphate and silicate additives are "used up"; coating surfaces against corrosion and cavitation - doing their job. It has the necessary anti-corrosion additives to protect cast iron, and lead solder from corrosion. It is fast acting, but because of the nature of those chemical reactions necessary to protect CI and Pb, is short lived.

Because of the intriguingly long-lived changing intervals advertised by the OAT brands, it is tempting to want to try them in our cars, but based on the above information about the chemistry involved that I found in my research on this subject, I have decided to keep using IAT for the above reasons.

By the way, there is very little "standardization" among makers, regarding color, and additive mix, so there are folks who have put together lists showing what each brand has / has not, and one good such list is in Wikipedia. //www.eetcorp.com/antifreeze/Coolants_matrix.pdf

Additional note: "hybrid OAT" is OAT with silicates, and also must be replaced every 24 months. This was used by some early GM, Ford and Chrysler systems, I suppose so that cast iron engine blocks would still get some protection. But moderns engines are almost all aluminum these days, so maybe that is why no one uses them any more? Something new I learned too was to never mix brands, or, no more than 10% mix, as their various chemical additive packages can react with each other in unfriendly ways, causing clogging.

IAT = Inorganic Additive Technology OAT = Organic Additive Technology HOAT = Hybrid OAT

You have to watch out because there are several colors of OAT in the market. Please check out the wiki link in my earlier post which gives colors (of most of them). The fact that there is no standard for color has caused a great deal of confusion.

Norm

In reply to OP's original question: extended life coolants are not designed for our cast iron engines and copper radiators, they are designed for all aluminum engines/radiators and lack some key ingredients that are needed to prevent corrosion in cast iron.

The parts guy recommended you use the old fashioned "green" coolant for that reason.

The way that the corrosion inhibitors work, with cast iron, is they sacrifice themselves, and as a result need to be changed every 24 months to maintain the protection.

Norm

Use whatever dont stain as bad,maybe incase there us an issue ... Buddy of mine had a hose burst and was on the side of the road and to this day you can see marks from where the coolant was on his paint.

there you go, a green coolant, this is what i use.

 

one of the worst design in mini parts is the radiator, it does not have a drain outlet!!!! my goodness! 

was it a mistake that they didnt put a drain on it?? or is there a purpose??  is it a market strategy??? 

well anyway, just venting out

I feel a bit silly asking this question. Here goes. I went to auto parts supplier A to get an extended life coolant. It was  the store brand was for 5 years. I happened to go to another auto parts supplier B and asked about coolants because he had a whole array of them. He told me to use the green stuff which was original to the mini. Now should I take his advice or use the extended coolant. I ask this because the last time I because I never changed the coolant and it's been twenty years. The stuff I drained out was just rusty water.